Beacons in wireless communication

karthikpnair, hi!

Please answer a question for me for my own curiosity... A lot of foreign questions seem to be answered by simply directing the questioner to either a Google site or to Wikipedia. Why is this? Are these resources blocked in your own countries or are these resources not translated extensively enough in your countries to know that the resources exist.

Please don't get me wrong. I am not complaining. I am just curious, and I have no problem pointing you to a good resource for information. I'd just like to know.

Anyway, here's what I found on Wikipedia. I hope it is enough, if not, please come on back and we will try to find you better information.

http://en.wikipedia.org/wiki/Zigbee

Perhaps, people love hiring teacher without paying salary. I agree that, people should do some home work and take help only when they are fish out of water. Forums of this type which is engineering type, means to be for help to experts and all those in trouble and want some SOS help. People ask such a silly question that they do not sound like engineer. Perhaps here is the case of not understanding the word "Beacons" and that is language problem. While abroad this is very common thing in other countries it is more used like alarm or signaling device. Now that I used the words that the person understands, it will be much easier to figure out the rest.

Beacon sounds like B52 bomber or a cruise missile about to hit you. Alarm right inside one's pocket may not sound all that bad. Some words are not common in some countries and never used in public.

I understand what you are saying and agree with you. I was hoping to get a reply from the poster and find out whether some resources are blocked from people in various countries.

For example, I knew a guy that had to work during Super Bowl Sunday #30. During the day he went on line and searched for "Super Bowl XXX." He was replied by an in-company message that said, "Please do not try to reach XXX sites on company facilities."

A mistake, but is this what's happening to other browsers of innocent information?

First , I believe he did try. But googling in English or in any other language requires you to think "google." If you don't, the amount of non-topic information you get is overwhelming, and is usually very frustrating. So, the easy way out, Well you have already said.

Wangito.

Good point! An avalanche of info... But it's all the wrong info.

Well put!!

Hi Vermin ,

Thanks for that link.

Thank you all for replying to the post. Actually i got my doubt while reading this

"The IEEE 802.15.4 MAC defines four frame structures:

· A beacon frame, used by a coordinator to transmit beacons.

· A data frame, used for all transfers of data.

· An acknowledgment frame, used for confirming successful frame reception.

· A MAC command frame, used for handling all MAC peer entity control transfers."

Here I dont think beacons will pass as wireless devices as told above.

From what you posted, I'm thinking that wireless is "connection-oriented" rather than connectionless.

In connection oriented protocols, the two devices use handshaking and a lot of messages passed back and forth, like "I'm going to send something"

"OK, send it to me."

"Did you get it?"

"Yes, I got it."

"Now I'm going to send you something, are you ready?"

"Yes, I am ready..." and so on.

In connectionless protocols, such as IP, this sort of communication does not occur.

Also, remember (with the exception of spoofing) each networking device has a unique MAC address that is shared by no other device in the world!!!

In this structure beacon frame is to announce its presence to others rather than giving any data. This takes minimum energy smallest time slot and its repeat rate is set at desired level of urgency. It can also change its repeat rate dynamically if so programmed in the device. You can also call it an assisting signal for tracking the device or for setting further dialog with others who may be there but may be silent now. Beacon may also carry ID information in some format which can be decoded to identification and to remove confusion and in that case it consumes more power. Beacom rate decreses as power to the devices goes down to elongate its life for likely detection.

You should have brought out this point right in the very first communication. It makes a lot of sense and removes confusion.

In ham radio, beacon has two meanings:

First, a beacon is a transmitter that automatically repeats the operator's callsign and the transmitter location. The purpose of a beacon station is to track long distance radio wave propagation. If a ham hears a beacon on a certain band when he normally can't, he knows that band is "open" for long-range contacts.

Second, "beacon" refers to a setting in APRS, Automatic Position Reporting System. APRS uses a series of digital repeaters to relay GPS and/or weather information. The beacon rate is how often a station transmits the information.

In short, a beacon is one-way communication.